/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.apache.catalina;

import javax.servlet.MultipartConfigElement;
import javax.servlet.Servlet;
import javax.servlet.ServletException;
import javax.servlet.UnavailableException;

/**
 * A <b>Wrapper</b> is a Container that represents an individual servlet
 * definition from the deployment descriptor of the web application.  It
 * provides a convenient mechanism to use Interceptors that see every single
 * request to the servlet represented by this definition.
 * <p>
 * Implementations of Wrapper are responsible for managing the servlet life
 * cycle for their underlying servlet class, including calling init() and
 * destroy() at appropriate times, as well as respecting the existence of
 * the SingleThreadModel declaration on the servlet class itself.
 * <p>
 * The parent Container attached to a Wrapper will generally be an
 * implementation of Context, representing the servlet context (and
 * therefore the web application) within which this servlet executes.
 * <p>
 * Child Containers are not allowed on Wrapper implementations, so the
 * <code>addChild()</code> method should throw an
 * <code>IllegalArgumentException</code>.
 *
 * @author Craig R. McClanahan
 */
public interface Wrapper extends Container {

	/**
	 * Container event for adding a wrapper.
	 */
	public static final String ADD_MAPPING_EVENT = "addMapping";

	/**
	 * Container event for removing a wrapper.
	 */
	public static final String REMOVE_MAPPING_EVENT = "removeMapping";

	// ------------------------------------------------------------- Properties

	/**
	 * Return the available date/time for this servlet, in milliseconds since
	 * the epoch.  If this date/time is in the future, any request for this
	 * servlet will return an SC_SERVICE_UNAVAILABLE error.  If it is zero,
	 * the servlet is currently available.  A value equal to Long.MAX_VALUE
	 * is considered to mean that unavailability is permanent.
	 */
	public long getAvailable();

	/**
	 * Set the available date/time for this servlet, in milliseconds since the
	 * epoch.  If this date/time is in the future, any request for this servlet
	 * will return an SC_SERVICE_UNAVAILABLE error.  A value equal to
	 * Long.MAX_VALUE is considered to mean that unavailability is permanent.
	 *
	 * @param available The new available date/time
	 */
	public void setAvailable(long available);

	/**
	 * Return the load-on-startup order value (negative value means
	 * load on first call).
	 */
	public int getLoadOnStartup();

	/**
	 * Set the load-on-startup order value (negative value means
	 * load on first call).
	 *
	 * @param value New load-on-startup value
	 */
	public void setLoadOnStartup(int value);

	/**
	 * Return the run-as identity for this servlet.
	 */
	public String getRunAs();

	/**
	 * Set the run-as identity for this servlet.
	 *
	 * @param runAs New run-as identity value
	 */
	public void setRunAs(String runAs);

	/**
	 * Return the fully qualified servlet class name for this servlet.
	 */
	public String getServletClass();

	/**
	 * Set the fully qualified servlet class name for this servlet.
	 *
	 * @param servletClass Servlet class name
	 */
	public void setServletClass(String servletClass);

	/**
	 * Gets the names of the methods supported by the underlying servlet.
	 * <p>
	 * This is the same set of methods included in the Allow response header
	 * in response to an OPTIONS request method processed by the underlying
	 * servlet.
	 *
	 * @return Array of names of the methods supported by the underlying
	 * servlet
	 */
	public String[] getServletMethods() throws ServletException;

	/**
	 * Is this servlet currently unavailable?
	 */
	public boolean isUnavailable();

	/**
	 * Return the associated servlet instance.
	 */
	public Servlet getServlet();

	/**
	 * Set the associated servlet instance
	 */
	public void setServlet(Servlet servlet);

	// --------------------------------------------------------- Public Methods

	/**
	 * Add a new servlet initialization parameter for this servlet.
	 *
	 * @param name  Name of this initialization parameter to add
	 * @param value Value of this initialization parameter to add
	 */
	public void addInitParameter(String name, String value);

	/**
	 * Add a new listener interested in InstanceEvents.
	 *
	 * @param listener The new listener
	 */
	public void addInstanceListener(InstanceListener listener);

	/**
	 * Add a mapping associated with the Wrapper.
	 *
	 * @param mapping The new wrapper mapping
	 */
	public void addMapping(String mapping);

	/**
	 * Add a new security role reference record to the set of records for
	 * this servlet.
	 *
	 * @param name Role name used within this servlet
	 * @param link Role name used within the web application
	 */
	public void addSecurityReference(String name, String link);

	/**
	 * Allocate an initialized instance of this Servlet that is ready to have
	 * its <code>service()</code> method called.  If the servlet class does
	 * not implement <code>SingleThreadModel</code>, the (only) initialized
	 * instance may be returned immediately.  If the servlet class implements
	 * <code>SingleThreadModel</code>, the Wrapper implementation must ensure
	 * that this instance is not allocated again until it is deallocated by a
	 * call to <code>deallocate()</code>.
	 *
	 * @throws ServletException if the servlet init() method threw
	 *                          an exception
	 * @throws ServletException if a loading error occurs
	 */
	public Servlet allocate() throws ServletException;

	/**
	 * Return this previously allocated servlet to the pool of available
	 * instances.  If this servlet class does not implement SingleThreadModel,
	 * no action is actually required.
	 *
	 * @param servlet The servlet to be returned
	 * @throws ServletException if a deallocation error occurs
	 */
	public void deallocate(Servlet servlet) throws ServletException;

	/**
	 * Return the value for the specified initialization parameter name,
	 * if any; otherwise return <code>null</code>.
	 *
	 * @param name Name of the requested initialization parameter
	 */
	public String findInitParameter(String name);

	/**
	 * Return the names of all defined initialization parameters for this
	 * servlet.
	 */
	public String[] findInitParameters();

	/**
	 * Return the mappings associated with this wrapper.
	 */
	public String[] findMappings();

	/**
	 * Return the security role link for the specified security role
	 * reference name, if any; otherwise return <code>null</code>.
	 *
	 * @param name Security role reference used within this servlet
	 */
	public String findSecurityReference(String name);

	/**
	 * Return the set of security role reference names associated with
	 * this servlet, if any; otherwise return a zero-length array.
	 */
	public String[] findSecurityReferences();

	/**
	 * Increment the error count value used when monitoring.
	 */
	public void incrementErrorCount();

	/**
	 * Load and initialize an instance of this servlet, if there is not already
	 * at least one initialized instance.  This can be used, for example, to
	 * load servlets that are marked in the deployment descriptor to be loaded
	 * at server startup time.
	 *
	 * @throws ServletException if the servlet init() method threw
	 *                          an exception
	 * @throws ServletException if some other loading problem occurs
	 */
	public void load() throws ServletException;

	/**
	 * Remove the specified initialization parameter from this servlet.
	 *
	 * @param name Name of the initialization parameter to remove
	 */
	public void removeInitParameter(String name);

	/**
	 * Remove a listener no longer interested in InstanceEvents.
	 *
	 * @param listener The listener to remove
	 */
	public void removeInstanceListener(InstanceListener listener);

	/**
	 * Remove a mapping associated with the wrapper.
	 *
	 * @param mapping The pattern to remove
	 */
	public void removeMapping(String mapping);

	/**
	 * Remove any security role reference for the specified role name.
	 *
	 * @param name Security role used within this servlet to be removed
	 */
	public void removeSecurityReference(String name);

	/**
	 * Process an UnavailableException, marking this servlet as unavailable
	 * for the specified amount of time.
	 *
	 * @param unavailable The exception that occurred, or <code>null</code>
	 *                    to mark this servlet as permanently unavailable
	 */
	public void unavailable(UnavailableException unavailable);

	/**
	 * Unload all initialized instances of this servlet, after calling the
	 * <code>destroy()</code> method for each instance.  This can be used,
	 * for example, prior to shutting down the entire servlet engine, or
	 * prior to reloading all of the classes from the Loader associated with
	 * our Loader's repository.
	 *
	 * @throws ServletException if an unload error occurs
	 */
	public void unload() throws ServletException;

	/**
	 * Get the multi-part configuration for the associated servlet. If no
	 * multi-part configuration has been defined, then <code>null</code> will be
	 * returned.
	 */
	public MultipartConfigElement getMultipartConfigElement();

	/**
	 * Set the multi-part configuration for the associated servlet. To clear the
	 * multi-part configuration specify <code>null</code> as the new value.
	 */
	public void setMultipartConfigElement(
			MultipartConfigElement multipartConfig);

	/**
	 * Does the associated Servlet support async processing? Defaults to
	 * <code>false</code>.
	 */
	public boolean isAsyncSupported();

	/**
	 * Set the async support for the associated servlet.
	 */
	public void setAsyncSupported(boolean asyncSupport);

	/**
	 * Is the associated Servlet enabled? Defaults to <code>true</code>.
	 */
	public boolean isEnabled();

	/**
	 * Sets the enabled attribute for the associated servlet.
	 */
	public void setEnabled(boolean enabled);

	/**
	 * Set the flag that indicates
	 * {@link javax.servlet.annotation.ServletSecurity} annotations must be
	 * scanned when the Servlet is first used.
	 *
	 * @param b The new value of the flag
	 */
	public void setServletSecurityAnnotationScanRequired(boolean b);

	/**
	 * Scan for (if necessary) and process (if found) the
	 * {@link javax.servlet.annotation.ServletSecurity} annotations for the
	 * Servlet associated with this wrapper.
	 */
	public void servletSecurityAnnotationScan() throws ServletException;

	/**
	 * Is the Servlet overridable by a ServletContainerInitializer?
	 */
	public boolean isOverridable();

	/**
	 * Sets the overridable attribute for this Servlet.
	 */
	public void setOverridable(boolean overridable);
}
